Effects of fluvastatin on structure and function of resistant vessels in spontaneously hypertensive rats

AIM: To evaluate the effects of fluvastatin, a hydroxymethylglutaryl-CoA (H MG-CoA) reductase inhibitor, on the alterations of structure and function o f resistant vessels in spontaneously hypertensive rats (SHR). METHODS: Eigh t-week-old male SHR were given fluvastatinn 20 mg.kg(-1). d(-1) by gavage. Rats were decapitated at 16 wk. Wall-to-lumen area ratios (W/L) of thoracic aorta and mesenteric arteries (3rd grade branch) were assessed by morphome tric assay. The effects of fluvastatin on vascular reactivity to sodium nit roprusside (SNP) and norepinephrine (NE), were studied with rings of thorac ic aorta and mesenteric arteries isolated from rats. RESULTS: After 8 wk of treatment, histological examination showed that the wall-to-lumen area rat io was lower in SHRflu, than that in SHR (0.44 +/- 0.09 vs 0.79 +/- 0.09, P < 0.05). EC50 Of vasodilation response was much lower in SHRflu, than that in SHR [(4.9 vs 190) pmol. L-l, P < 0.05], while EC50 Of mesenteric artery rings from SHRflu, was somewhat lower than that of SHR [(0.02 vs 0.04) nmo l.L-1, P > 0.05]. In both aortic and mesenteric artery rings, EC50 Of vasoc onstriction in response to NE from SHRB, was higher than that of SHR [thora cic aorta: (0.20 vs 0.02) nmol L-1, P < 0.05; mesentric arteries: (1.46 vs 0.72) nmol.L-1, P < 0.05]. CONCLUSION: Short-term treatment with fluvastati n ameliorated the vasomotoricity of resistant vessels, enhanced the sensiti vity to vasodilator and depressed the sensitivity to vasoconstrictor; fluva statin also attenuated the resistant vascular hypertrophy during the develo pment of hypertension in SHR.